Ocular torsion during head tilt, a method of assessing the inferior vestibular nerve pathway

Introduction: Functions of the normal human balance system include postural control and gaze stabilisation. The latter requires accurate lateral and torsional eye movement. We recently acquired cVEMP and videonystagmography recording equipment and reassessed patients diagnosed with bilateral vestibular hypofunction in order to optimise their customised vestibular rehabilitation.

Methods: Patients with caloric confirmed bilateral vestibular hypofunction were identified. Each was invited to undergo cVEMP testing in order to assess their inferior vestibular nerve function. Eye movements were also recorded during active and passive head movements.

Results: Twenty-eight patients with bilateral vestibular hypofunction attended in order to assess their inferior vestibular nerve function. Of these 25 demonstrated normal cVEMP responses and normal ocular torsion on active and passive head tilt. Three subjects failed to elicit normal cVEMP responses. In each case pendular ocular torsion was demonstrated on active and passive head tilt.

Discussion: This observation suggests that assessing ocular torsion may provide a simple alternative to cVEMP testing and merits further research.